Distinctive paper and method of making same



Patented Jan. 19, 1937 UNITED STATES PATENT oFFicE' v ,2,067,988DISTINCT-IVE PAPER METHOD or MAKING SAME Burgess W. Smith, Rochester, N.Y., assignor. to The Todd Company, Inc., Rochester, N. Y., a corporationof New York No Drawing. Application April 23,.1934, Serial No. 721,977

time to prove the authenticityof'the document and further toprovidemeans-by which the use of chemicals is avoided, and if sodesired, means to cancel the doc'umentto-prevent there-use of the paper.

- i To these and other ends,'the1invention'resides in certaincombinations and improvements herechettes, silk fibres, water-marks,andother similar papers-methods admitting simulation or actualduplication of which are well known in the arts. Another class c-fdistinctive papers contain certain chemicals therein which react toproduce a color or other chemical reaction on the application of certainreagents. The determination of the authenticity of such papers requiresthe possession of these chemicals which, at times, is inconvenient andimpractical.

By the means of my invention, it ispossible to produce a distinctivepaper containing a word or symbol that may be developed at any time bythe mere application of water which, ordinarily, is always available forthe purpose and its duplication requires expensive and ponderousmachinery.

I accomplished this invention by the partial or complete destruction ofthe sizing effect of ordinary paper so as to. form on the ground of theuntreated paper the desired word or symbol, so that when it is immersedor otherwise treated with water, the paper will absorb it into the bodyof the paper making it more translucent than the area not so treated,thereby making visible the desired insignia.

I accomplished this by immersion of the paper into a solution that willpermanently reduce the surface tension of the sizing to the desiredextent and cause the solution to penetrate into the body of the paper bypressure of a roll engraved with characters that it is desired toproduce which will be invisible when the paper is dry. The apparatus andmethod of producing visible characters on paper, using a solution ofdye, is well known in the art and is amply described in the patentissuedto LaMonte, No. 123,782, dated February 20, l872,'and others.

The solution used for this purpose may be varied to any 'extent toconform with the nature of the paper, the amount of pressure andtheconstruction of the machine. I find that a mixture of 10% solution ofborax and a 5% solution of tribaslo sodium phosphate, equal parts ofeach,

is generally satisfactory for this purpose but to securea moreperfectresult, I add one quarter of 1% of the sodium salt of the sulphuric acidester of lauryl alcohol which accelerates and greatly augmentsthedestruction of the sizing where the 1 paper is impressed'with-thedesired characters.

" The paper, after beingimpressed with the desired characters, may berun through-a set of squeeze rolls to remove the surplus solutionanddried; or the surplus solution may be removed by immersion in water, thesurplus water being squeezed out and the paper then dried; or anyvariation that may be indicated by the nature of the'sizing effect ofthe paper, the exact details being obvious to those skilled in this'art.

After this paper is dried, the sizing effectber tween the marked andunmarked areas is so dis-- turbed and alteredthat upon the applicationof water or immersion in that liquid, thecharacters will absorb morethan the ground, making them plainly discernible, although theoperation, when skillfully done, does not alter the appearance. Afterthe characters have been developed by such means, the paper may be driedwhen they will disappear and can be redeveloped; at any time byimmersion or otherwise applying water in the or characters will absorbthe ink selectively so that the identifying words or characters nolonger disappear, an indication that the label has been developed.

To accomplish this effect in a more thorough manner, I may incorporatein the solutions a substance that acts as a mordant for the color thatwould be used for printing the label or I may coat the back withinteracting chemicals, such as on one side iron salt and on the other aprussiate, which chemicals being separated by an insulating membrane ofthe paper do not interact until the paper is wet, when they will, andproduce a significant color selectively in the letters or designoriginally produced in the paper by the process outlined.

I am aware that paper has been treated to disturb the sizing effect soas to produce words or designs upon the application of water but I amnot aware, before my invention, of the production of words or designs inthe manner described; I am not aware of the incorporation of reactivechemicals on opposite sides of a paper when the' sizing effect has beendisturbed in the manner outlined, or in any other way, so that upon theap-. Y

plication of water, the disturbed sizing efiect will admit of theproduction by reason of the combination of said chemicals of a word ordesign for the'purpose outlined.

I do notlimit the scope of this invention to the specific materialsdescribed or to use water in producing this effect. I may use alcohol orother liquids in combination with paper that has a sizing effect thatmay be selectively destroyed by the method I have described. Theessential feature of this invention is the selective destruc tion of thesizing effect by causing more of the active material to enter into thepaper and de-- stroy the sizing effect wherein impressed while wet withsaid solution.

It is not essential that the selective destruction I of sizing effect inthis manner be renderedgvisible by water. The active bath may be sodesigned that it will cause the words, characters or designs to appearwhen moistened with oils or. other liquids.

I claim:

1. A distinctive paper having hidden words, characters or designs formedby selectivevariation in the sizing effect, coated on opposite sideswith interacting chemicals adapted to develop and render permanentlyvisible said words, characters or designs when said paper is wet with aliquid.

2. The method of producing a distinctive paper which consists in firstsubjecting a dry sized paper stock to the action of a colorless liquidcapable of modifying the surface sizing of the paper, then impressingsaid paper stock, while wet with the said liquid, with a member engravedwith predetermined indicia to selectively increase the penetration ofsaid liquid and the said modification of the sized surface thereby atthe impressed areas to form normally invisible markings, and thereafterdrying said paper stock, whereby when paper is moistened said markingsare rendered visibly distinct from the unimpressed area.

pressed areas to form normally invisible markings, and thereafter dryingsaid paper stock; and printing thereon a visible indicia with apermanentink adapted to be removed by abrasive treat- 'ment of saidpaper to afford a warning of attempted erasure of any subject matterinscribed on said paper. I 1

4. The methodsof producing a distinctive paper which consists in firstsubjecting a dry sized paper stock to the action of a colorless liquidcapable ofmodifying the surface sizing of the paper, then impressingsaid paper stock, while wet with the said liquid, with a member engravedwith predetermined indicia to selectively increase the penetrationofsaid liquidand the said modification of the sized surface thereby at theimpressed areas to form normally invisible markings, and

- thereafter drying said paper stock; and printing .thereon a visibledesign or other subject matter with asensitivewater soluble ink, wherebywhen said paper is moistened the sensitive ink is absorbed by saidmodifications in the sized surface of said paper to permanently mark thesame and afford a visible warning that said paper has once beendeveloped. a

BURGESS W-. SMITH.

